docstr: Append 'item' to the list at 'key'.  If no list exists for 'key', then
  construct one.
docstr_tok: ["Append","'item","'","to","the","list","at","'key","'",".","If","no","list","exists","for","'key","'",",","then","construct","one","."]
code: def safeappend(self, key, item):
      """
      Append 'item' to the list at 'key'.  If no list exists for 'key', then
      construct one.
      """
      if key not in self:
          self[key] = []
      self[key].append(item)
  
file_path: nltk/nltk/sem/lfg.py
imports: from itertools import chain
  from nltk.internals import Counter
label_desc: Use image node_id 1 for calling the FStructure obj's underlying member method code with example usage: obj.safeappend(key, item) without return types